首页
登录
职称英语
At the present time, 98 percent of the world energy consumption comes from s
At the present time, 98 percent of the world energy consumption comes from s
游客
2025-04-26
11
管理
问题
At the present time, 98 percent of the world energy consumption comes from stored sources, such as fossil fuels or nuclear fuel. Only hydroelectric and wood energy represent completely renewable sources on ordinary time scales. Discovery of large additional fossil fuel reserves, solution of the nuclear safety and waste disposal problems, or the development of controlled thermonuclear fusion will provide only a short-term solution to the world’s energy crisis. Within about 100 years, the thermal pollution resulting from our increased energy consumption will make solar energy a necessity at any cost.
Man’s energy consumption is currently about one part in ten thousand that of the energy we receive from the sun. However, it is growing at a 5 percent rate, of which about 2 percent represents a population growth and 3 percent a per capita energy increase. If this growth continues, within 100 years our energy consumption will be about 1 percent of the absorbed solar energy, enough to increase the average temperature of the earth by about one degree centigrade if stored energy continues to be our predominant source. This will be the point at which there will be significant effects in our climate, including the melting of the polar ice caps, a phenomenon which will raise the level of the oceans and flood parts of our major cities. There is positive feedback associated with this process, since the polar ice cap contributes to the partial reflectivity of the energy arriving from the sun: As the ice caps begin to melt, the reflectivity will decrease, thus heating the earth still further.
It is often stated that the growth rate will decline or that energy conservation measures will preclude any long-range problem. Instead, this only postpones the problem by a few years. Conservation by a factor of two together with a maintenance of the 5 percent growth rate the problem by only 14 years. Reduction of the growth rate to 4 percent postpones the problem by only 25 years; in addition, the inequities in standards of living throughout the world will provide pressure toward an increase in growth rate, particularly if cheap energy is available. The problem of a changing climate will not be evident until perhaps ten years before it becomes critical due to the nature of an exponential growth rate together with the normal annual weather variations. This may be too short a period to circumvent the problem by converting to other energy sources, so advance planning is a necessity.
The only practical means of avoiding the problem of thermal pollution appears to be the use of solar energy. (Schemes to "air-condition" the earth do not appear to be feasible before the twenty-second century. ) Using the solar energy before it is dissipated to heat does not increase the earth’s energy balance. The cost of solar energy is extremely favorable now, particularly when compared to the cost of relocating many of our major cities. [br] The author is primarily concerned with ______.
选项
A、describing a phenomenon and explaining its causes
B、outlining a position and supporting it with statistics
C、isolating an ambiguity and clarifying it by definition
D、presenting a problem and advocating a solution for it
答案
D
解析
作者主要是提出问题并提倡一种解决问题的方法。作者在第一段最后一句提出了热污染问题,在最后一段首句指出了消除热污染的方法,即利用太阳能。
转载请注明原文地址:https://tihaiku.com/zcyy/4054460.html
相关试题推荐
Theenergycrisis,whichisbeingfeltaroundtheworld,hasdramatizedhowth
Theenergycrisis,whichisbeingfeltaroundtheworld,hasdramatizedhowth
Theenergycrisis,whichisbeingfeltaroundtheworld,hasdramatizedhowth
Onekeyquestionforthenextcenturyishowwewillprovideenergyinanen
Onekeyquestionforthenextcenturyishowwewillprovideenergyinanen
Atthepresenttime,98percentoftheworldenergyconsumptioncomesfroms
Atthepresenttime,98percentoftheworldenergyconsumptioncomesfroms
Atthepresenttime,98percentoftheworldenergyconsumptioncomesfroms
Theenergycrisis,whichisbeingfeltaroundtheworld,hasdramatizedhow
Theenergycrisis,whichisbeingfeltaroundtheworld,hasdramatizedhow
随机试题
【1】[br]【9】[originaltext]Goodmorning.Intoday’slecture,weshalldiscus
NEWHORIZONS Areyoulookingforsomethinginterestingtodo?
AfterthreeyearsatNewYorkUniversity,Ileftatthetimetotakeasix-m
在工程项目进度控制计划系统中,由建设单位负责编制的总进度计划表包括()。A:工
弯矩、剪力和扭矩共同作用的弯剪扭混凝土构件,剪力与扭矩、弯矩与扭矩均存在相关性,
货币经纪公司可以向境内外金融机构提供经纪服务,也可以从事金融产品的自营业务(
某地对多栋建筑的消防应急照明和疏散指示系统进行验收,经过分析整理,得出下列判定结
悬饮后期,络气不和,当选( ) A.香附旋覆花汤 B.已椒苈黄汤 C.十
客户姓名或者名称、有效身份证明文件号码和客户期货结算账户户名之外的客户信息,监控
现阶段,深化预算管理制度改革的主要内容有()。A.完善政府预算体系 B.实行中
最新回复
(
0
)